Sunsynk F23: AC Leakage Current (Transient)
F23 means your Sunsynk briefly detected leakage current to ground above its threshold. The key word is transient: it is often a passing event, commonly caused by moisture in the panel wiring after rain or heavy dew. It frequently clears after one or two automatic restarts. If it keeps coming back, though, it points to a real wiring or grounding issue worth inspecting.
What usually causes F23
- Moisture or condensation in a DC connector, junction box or cable gland, most common early morning or after rain.
- Aging or slightly damaged cable insulation letting a small current leak.
- A grounding issue in the PV array or system earth.
- High humidity in general, which can nudge a marginal system over the line.
How to handle it safely
No opening connectors Inspecting or repairing DC wiring is an installer job. Your safe role is to let it self-clear and watch the pattern.
- Let it self-clear. F23 often clears after one or two automatic restarts, especially once morning moisture dries off.
- Note the pattern. Does it only happen early morning, after rain or in humid weather? That points to moisture and usually is not urgent.
- Power-cycle once if needed. AC off, then the DC isolator, wait five minutes, restart.
- Watch the clock. If F23 hangs around for more than about an hour, or keeps returning even in dry weather, it is no longer just transient moisture.
Quick decision flowchart
F23 appears
↓ does it clear within an hour, mostly in damp conditions?
✅ Yes → likely transient moisture. Keep an eye on it; not urgent.
❌ No, persists or returns when dry → real leakage or grounding issue.
↓
If it persists or recurs in dry weather, book your installer to inspect the DC connectors, cables and grounding.
When to bring in a professional
Persistent or dry-weather F23 means a genuine insulation, connector or grounding fault. Leakage current is a safety matter, so have a licensed installer inspect the PV wiring rather than ignoring repeated alarms.
Related Sunsynk codes
FAQ
F23 shows every morning then goes away.
That classic pattern usually means overnight moisture or dew on the DC wiring that burns off as things dry and warm up. Worth mentioning at the next service, but a brief morning F23 that clears is rarely urgent.
Can I fix the moisture myself?
No. Finding and sealing a damp connector is DC work for a qualified installer. You can note the pattern and report it, but don't open connectors yourself.
Sources
- Sunsynk Hybrid Inverter User Manual (F23 = AC leakage transient current; check PV side ground, restart 2-3 times).
- Sunsynk fault-code references and installer documentation.
⚠️ Safety disclaimer. Leakage current involves electrical safety. Solar inverters carry lethal DC and AC voltage. This guide covers letting the code self-clear and a single safe power cycle only. Inspection and repair of DC wiring and grounding must be done by a licensed installer or electrician.